Mining machine cutter bit



April 3, 1951 P. JOHNSON MINING MACHINE CUTTER BIT Filed March 13, 1947 .M m H INV EN'I'OR ATTORNEYS Patented Apr. 3, 1951 UNITED STATES MINING MACHINE CUTTER BIT Parker L. Johnson, Hazard, Ky.

Application March 13, 1947, Serial No. 734,487

This invention relates to newand useful im= provements in cutter chain bits for coal cutting machinery of which the following is a specification.

' The primary object of this invention resides in the provision of a cutter chain bit which is preformed separately from the cutter chain with a double pointed structure adapting it to be reversibly removably carried one by each link of the cutter chain.

Another object of this invention is the provision of a cutter chain bit of the qualities set forth which is retained directly by the individual link of the cutter chain and the bit construction adapts it to be self-adjusting relative to the link during th securing operation.

Another and still further object of this invention is the provision of a cutter chain bit which is adapted to be manufactured from an alloyed steel with a small cutting area exposed to the coal which performs a fine cutting operation of the coal, rather than the undesirable crushing action inherent in the majority of those coal ma chinery cutters now in use. i

Still a further object of this invention is the provision of a cutter chain bit which can be easily and properly preformed and sharpened as desired, and a bit which having two points and being reversible adapts a single bit to give double performance while'in the mine before removal for sharpening becomes necessary. Additionally the bit can only be secured in its proper position relative to the link of the cutter chain eliminating the necessary gauging and adjustment thereof when being initially placed in said link.

Still further improvements and advantages of this invention will readily appear to those skilled in the art when the following description is read in the light of the accompanying drawings in which: 7

Fig. 1 is a side elevation of the bit and a single link.

Fig. 2 is a top plan view of the bit.

Fig. 3 is a bottom plan view of the bit.

Fig. 4 is a modified form of the bit and its cooperative link construction.

Referring now to the accompanying drawings which illustrate the preferred embodiment of this invention and in which like numerals in.

dicate similar parts throughout the drawings A designates a single link from a conventional cutter chain as used with coal cutting machinery. The link is provided with the conventional vertical bit receiving chamber centrally formed 1 Claim. (Cl. 262-33) from the upper surface 2 of the link, and a con- M rem" OFFICE ventional' cup or ball point set screw 3 threadably carried in a horizontal drilled bore 4 opening from the forward face of said link through the forward wail of said chamber intermediate its height.

In the conventional type of construction now in use a straight edged shank of a single pointed tool bit is manually adjusted at the proper ver tical height within a chamber, so as to correctly gauge the position of the cutter bit point above a link, and the set screw is then tightened to cause the bit engaging end thereof to bite into the shank of the bit to secure it in the desired cutting position. 7

In the preferred embodiment of this invention a preformed alloyed steel cutter bit B is provided which is formed with a cutting edge or point 6 disposed one at each end thereof from the same of the bit with a straight face I of the bit joining the base of the back rakes 8 and the side rakes 9 of each of the points adapting the bit to be disposed with the face 1' in a vertical flush position adjacent the rearward wall of the chamber I. The face Hi of the bit, opposite the face 1 and interconnecting the points of the bit, is provided adjacent each point with a symmetrical inwardly curved portion ll, said portions being curved outwardly again at points near the transverse center-line of said bit where the straight face edge [0 bridges the inward ends of said curved rakes.

With the construction as set forth it may be readily seen that the face edge lil will be disposed vertically adjacent the forward wall of the chamber l forming a tight sliding fit between the bit and the chamber walls, and with the preformed gauged disposition of the curved back res relative to the length of the bit the ball point of the set screw will firmly engage said lower curved depression and automatically adjust said bit in a secure position within the link chamber with the upper cutting point properly positioned thereabove.

In the modification set forth in Fig. 4 the back rake l or" the bit 33 is reduced to a minimum standard rake and a pair of circular detents 20 are formed at predetermined spaced distances from the bases of the front rake inward the straight face I of the bit.

In this modified construction the set screw 3' is carried the rear of the link into the rearward wall of the chamber I in a manner adaptit to the lowermost detent 2i] to secure and automatically adjust the bit within, and relative to, the link.

Thus it may be seen that a new and improved construction has been provided for a cutter chain bit which embodies a reversible bit having two cutting points thereon, which is preformed from an alloy steel offering a finer cutting point to the coal, and also a bit which will be adjusted automatically to a gauged height relative to the chain link as it is secured in place therein.

Having thus described and explained the construction and operation of the improved invention set forth, which has the advantages and objects set forth, and with full belief that modifications in size, materials used, and general characteristics would not constitute departure from the spirit of the invention what I desire to claim in Letters Patent is:

In a cutting chain, chain links, bit blocks having bit chambers, each chamber having a threaded opening formed in the front wall thereof, an elongated double ended bit reinovably fitted within the chamber of each link, the front and rear faces of the bit contacting the front and and engaging within a recess in the face of the bit adjusting and securing the bit within the bit chamber in which the bit is positioned.

PARKER L. JOHNSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,585,021 Zellers May 25, 1926 20 2,017,457 Hamilton Oct. 15, 1935 2,039,417 Holmes May 5, 1935 2,107,942 Holmes Feb. 8, 1938 

